The polling firm spoke to 154,000 people in 145 different countries, asking them about how they were feeling that day. The results, released on Thursday (NZ time), show worldwide negative experiences at their highest since polling began in 2006.

"Collectively, the world is more stressed, worried, sad and in pain today than we've ever seen it," Gallup managing editor Mohamed Younis wrote.

Worldwide, the Negative Experience index hit 30 - up from 23 in 2007. The corresponding Positive Experience Index dropped to 69, equal with its previous lows in the wake of the global financial crisis.

Photo credit: Gallup.

The countries with the highest Negative Experience scores are conflict, poverty and disease hotspots: Uganda, Madagascar, Liberia, Palestine, Niger, Iran, Egypt, Sierra Leone, Chad, South Sudan and, replacing second-placed Iraq at the top of the list, the Central African Republic.

Countries with the lowest Positive Experience scores are almost all dealing with internal conflict and strife: Afghanistan, Yemen, Tunisia, Turkey, Nepal, Ethiopia, Turkmenistan, Macedonia, Iraq, Serbia, Montenegro and Belarus. War-torn Syria was not included in the study this year.

So where in the world are people enjoying life? The top 10 Positive Experience scores came from Uzbekistan, Panama, Indonesia, Iceland, Honduras, Ecuador, Costa Rica, Canada, Guatemala, El Salvador, Colombia and top-of-the-table Paraguay.

Photo credit: Gallup.

"The high percentages reporting positive emotions in Latin America at least partly reflects the cultural tendency in the region to focus on life's positives," the report noted, saying there might be some "cultural bias" in how people respond to the questions.

Mr Younis says the research gives leaders an understanding of whether their citizens' lives are getting better or worse, in a way GDP can't measure.

The United Nations' World Happiness Report uses Gallup data, but collected in a different poll with a different methodology. Its latest report, released earlier this year, ranked the Scandinavian countries as the world's happiest - led by Finland.

The only non-Scandinavian countries to make the top 10 were Switzerland, Canada, Australia and New Zealand. The Central African Republic came second-to-last in that report, ahead of only tiny landlocked African country Burundi.